Battery monomer, battery device and electric equipment

Abstract

The utility model provides a battery monomer, a battery device and electric equipment. The battery monomer comprises a shell, an electrode assembly, a pressure relief mechanism and a current collecting component, the shell is provided with a wall part, the electrode assembly is accommodated in the shell, the pressure relief mechanism is arranged on the wall part, and the current collecting component is positioned between the electrode assembly and the pressure relief mechanism. The current collecting member includes a first connector and a second connector connected to each other, one of the first connector and the second connector is connected to the electrode assembly, and the other is connected to the case. The first connecting body is provided with an exhaust hole, and the projection of the second connecting body is at least partially located in the exhaust hole in the thickness direction of the wall part. The vent hole includes a first region covered by the second connector and a second region not covered by the second connector for guiding emissions within the battery cells to the pressure relief mechanism. And emissions in the single battery can flow to the pressure relief mechanism through the second area, so that the pressure building risk of the single battery is reduced, and the reliability of the single battery is improved.

Description

Technical Field

[0001] The present application relates to the field of batteries, and more particularly, to a battery cell, a battery device, and an electrical device. Background Art

[0002] Batteries are widely used in the new energy field, such as electric vehicles, new energy vehicles, etc. Electric vehicles and new energy vehicles have become new trends in the development of the automotive industry. The development of battery technology needs to consider multiple design factors at the same time. For example, performance parameters such as battery life, energy density, discharge capacity, charge and discharge rate, etc. In addition, the reliability of the battery also needs to be considered. However, the current batteries have poor reliability. Summary of the Utility Model

[0003] The purpose of the embodiments of the present application is to provide a battery cell, a battery device, and an electrical device, which aim to improve the problem of poor reliability of batteries in related technologies.

[0004] In a first aspect, the embodiments of the present application provide a battery cell. The battery cell includes a housing, an electrode assembly, a pressure relief mechanism, and a current collector member. The housing has a wall portion; the electrode assembly is accommodated in the housing; the pressure relief mechanism is disposed on the wall portion; the current collector member is located between the electrode assembly and the pressure relief mechanism; wherein, the current collector member includes a first connection body and a second connection body connected to each other. One of the first connection body and the second connection body is connected to the electrode assembly, and the other is connected to the housing. The first connection body is provided with an exhaust hole. Along the thickness direction of the wall portion, at least a part of the projection of the second connection body is located in the exhaust hole. The exhaust hole includes a first region covered by the second connection body and a second region not covered by the second connection body. The second region is used to guide the emissions in the battery cell to the pressure relief mechanism.

[0005] In the above technical solution, the first connection body of the current collector member is provided with an exhaust hole, and the exhaust hole has a second region not covered by the second connection body, so that the emissions in the battery cell can flow to the pressure relief mechanism through the second region, facilitating the rapid pressure relief of the battery cell, reducing the risk of pressure buildup in the battery cell, and being beneficial to improving the reliability of the battery cell.

[0006] As an optional technical solution of the embodiments of the present application, the second connection body includes a plurality of first connection portions. Along the thickness direction of the wall portion, the projection of the first connection portion is located in the exhaust hole, and the plurality of first connection portions are arranged at intervals along the circumferential direction of the exhaust hole on the first connection body.

[0007] In the above technical solution, by providing a plurality of first connection portions, on the one hand, the plurality of first connection portions are all connected to the wall portion or the electrode assembly, which is beneficial to increasing the current-carrying area. On the other hand, by arranging the plurality of first connection portions at intervals along the circumferential direction of the exhaust hole on the first connection body, the emissions in the battery cell can flow to the pressure relief mechanism through the area between two adjacent first connection portions, facilitating the rapid pressure relief of the battery cell and being beneficial to improving the reliability of the battery cell.

[0008] As an alternative technical solution of the embodiment of the present application, the second region includes a first hollowed-out area and a plurality of second hollowed-out areas. The plurality of first connection portions are arranged around the first hollowed-out area. The first hollowed-out area is communicated with the second hollowed-out areas, and one of the second hollowed-out areas is formed between two adjacent first connection portions.

[0009] In the above technical solution, by communicating the first hollowed-out area and the second hollowed-out areas, it is beneficial to increase the area of the second region, so that the emissions in the battery cell can quickly pass through the current collector member to reach the pressure relief mechanism, realizing the rapid pressure relief of the battery cell, reducing the risk of the battery cell being blocked by pressure, and being beneficial to improving the reliability of the battery cell.

[0010] As an alternative technical solution of the embodiment of the present application, the second connection body further includes a second connection portion. Along the thickness direction of the wall portion, the projection of the second connection portion is located in the exhaust hole, and the second connection portion connects the plurality of first connection portions.

[0011] In the above technical solution, by providing the second connection portion to connect the plurality of first connection portions, it is beneficial to increase the structural strength of the second connection body, making the first connection portion not easily deformed under external force, and being beneficial to making the connection between the first connection portion and the wall portion or the electrode assembly stable and reliable.

[0012] As an alternative technical solution of the embodiment of the present application, the second region includes a first hollowed-out area and a plurality of second hollowed-out areas. The plurality of first connection portions are arranged around the second connection portion. The first hollowed-out area is located within the second connection portion. The second connection portion separates the first hollowed-out area and the second hollowed-out areas, and one of the second hollowed-out areas is formed between two adjacent first connection portions.

[0013] In the above technical solution, a first hollowed-out area is further provided within the second connection portion, which is beneficial to increasing the area of the second region, reducing the risk of the battery cell being blocked by pressure, and being beneficial to improving the reliability of the battery cell.

[0014] As an alternative technical solution of the embodiment of the present application, the second connection portion is configured to be damaged when the battery cell is pressure-relieved.

[0015] In the above technical solution, the second connecting part is damaged when the battery cell is depressurized, so that the area of the second region is larger when the battery cell is depressurized, which is conducive to the emissions in the battery cell passing through the current collector member to the pressure relief mechanism quickly, realizing the rapid pressure relief of the battery cell, reducing the risk of pressure build-up in the battery cell, and being conducive to improving the reliability of the battery cell.

[0016] As an alternative technical solution of the embodiment of the present application, the pressure relief mechanism has a weak part, and the pressure relief mechanism is configured to crack along at least a part of the weak part when the battery cell is depressurized; the strength of the second connecting part is lower than the strength of the weak part.

[0017] In the above technical solution, by making the strength of the second connecting part lower than the strength of the weak part, when the battery cell is depressurized, the second connecting part is damaged under the action of the emissions in the battery cell, further increasing the area of the second region, which is conducive to the emissions in the battery cell passing through the current collector member to the pressure relief mechanism quickly, realizing the rapid pressure relief of the battery cell, reducing the risk of pressure build-up in the battery cell, and being conducive to improving the reliability of the battery cell.

[0018] As an alternative technical solution of the embodiment of the present application, the second connecting part is a ring structure.

[0019] In the above technical solution, when the second connecting part is a ring structure, the emissions of the battery cell can flow to the pressure relief mechanism through the inside of the ring structure, realizing the rapid pressure relief of the battery cell, reducing the risk of pressure build-up in the battery cell, and being conducive to improving the reliability of the battery cell.

[0020] As an alternative technical solution of the embodiment of the present application, the electrode assembly has a central hole, and along the thickness direction of the wall part, the projection of the hole wall surface of the central hole is located in the first hollow area.

[0021] In the above technical solution, when the projection of the hole wall surface of the central hole is located in the first hollow area, it indicates that the area of the first hollow area is larger than the area of the central hole, which is convenient for the emissions in the central hole to flow to the pressure relief mechanism through the first hollow area.

[0022] As an alternative technical solution of the embodiment of the present application, the electrode assembly has a tab, and the first connecting part is welded to the tab.

[0023] In the above technical solution, the first connecting part is welded to the tab, and the first connecting body is connected to the wall part, which can make reasonable use of space, make the connection between the current collector member, the electrode assembly and the wall part more stable, and is also conducive to making the manufacturing simpler and more convenient, reducing the manufacturing cost of the battery cell.

[0024] As an alternative technical solution of the embodiment of the present application, the first connecting part extends along the radial direction of the exhaust hole.

[0025] In the above technical solution, by making the first connecting portion extend along the radial direction of the exhaust hole, it is convenient for the first connecting portion to be connected to the wall portion or the electrode assembly. Especially for a cylindrical battery cell, the first connecting portion extending in the radial direction of the exhaust hole can just be electrically connected to the flattened tab.

[0026] As an alternative technical solution of the embodiment of the present application, the pressure relief mechanism has a weak portion, and the pressure relief mechanism is configured to crack along at least a part of the weak portion when the battery cell relieves pressure, and the weak portion defines a predetermined pressure relief area; along the thickness direction of the wall portion, the projection of the predetermined pressure relief area is located within the exhaust hole.

[0027] In the above technical solution, by making the projection of the predetermined pressure relief area located within the exhaust hole, on the one hand, the position of the predetermined pressure relief area corresponds to the position of the exhaust hole, which can facilitate the emissions in the battery cell to reach the pressure relief mechanism through the current collecting member. On the other hand, the area of the exhaust hole is large, which can achieve rapid pressure relief of the battery cell, reduce the risk of pressure buildup in the battery cell, and is beneficial to improving the reliability of the battery cell.

[0028] As an alternative technical solution of the embodiment of the present application, the pressure relief mechanism is provided with a pressure relief groove, and the pressure relief mechanism forms the weak portion in the area where the pressure relief groove is provided; along the thickness direction of the wall portion, the projection of the groove bottom surface of the pressure relief groove is located within the exhaust hole.

[0029] In the above technical solution, when the projection of the groove bottom surface of the pressure relief groove is located within the exhaust hole, the area of the exhaust hole is larger, and the pressure relief of the battery cell is smoother, which is beneficial to improving the timeliness of pressure relief of the battery cell.

[0030] As an alternative technical solution of the embodiment of the present application, the pressure relief mechanism has a weak portion, and the pressure relief mechanism is configured to crack along at least a part of the weak portion when the battery cell relieves pressure, and the weak portion defines a predetermined pressure relief area; along the thickness direction of the wall portion, the projection of the predetermined pressure relief area is at least partially located within the second region.

[0031] In the above technical solution, by making the projection of the predetermined pressure relief area at least partially located within the second region, that is, at least a part of the predetermined pressure relief area corresponds to the position of the second region, it can facilitate the emissions in the battery cell to reach the pressure relief mechanism through the current collecting member.

[0032] As an alternative technical solution of the embodiment of the present application, the pressure relief mechanism has a weak portion, and the pressure relief mechanism is configured to crack along at least a part of the weak portion when the battery cell relieves pressure, and the weak portion defines a predetermined pressure relief area; the area of the second region is larger than the area of the predetermined pressure relief area.

[0033] In the above technical solution, by making the area of the second region larger than the area of the predetermined pressure relief region, rapid pressure relief of the battery cell can be achieved, the risk of pressure buildup in the battery cell can be reduced, which is beneficial to improving the reliability of the battery cell.

[0034] As an alternative technical solution of the embodiment of the present application, the first connecting body is directly connected to the wall portion, and the second connecting body is connected to the electrode assembly.

[0035] In the above technical solution, by connecting the first connecting body to the wall portion and connecting the second connecting body to the electrode assembly, it is beneficial to simplify the manufacturing and reduce the manufacturing cost of the battery cell.

[0036] As an alternative technical solution of the embodiment of the present application, the housing includes a side wall that surrounds the wall portion and is connected to the wall portion; the first connecting body is directly connected to the side wall, and the second connecting body is connected to the electrode assembly.

[0037] In the above technical solution, by connecting the first connecting body to the side wall and connecting the second connecting body to the electrode assembly, on the one hand, the electrical energy of the electrode assembly can be output or electrical energy can be input to the electrode assembly through the side wall, which is convenient for wiring the battery cell with other electrical connection components. On the other hand, it is beneficial to simplify the manufacturing and reduce the manufacturing cost of the battery cell.

[0038] As an alternative technical solution of the embodiment of the present application, the pressure relief mechanism is integrally formed with the wall portion.

[0039] In the above technical solution, by integrally forming the pressure relief mechanism with the wall portion, no additional welding or bonding process is required, which is beneficial to reducing the risk of liquid leakage in the pressure relief mechanism. Moreover, during production, it is easy to make the detonation pressures of multiple processed battery cells relatively consistent.

[0040] As an alternative technical solution of the embodiment of the present application, the pressure relief mechanism is separately provided from the wall portion, the wall portion is provided with a pressure relief hole, and the pressure relief mechanism is installed on the wall portion and covers the pressure relief hole.

[0041] In the above technical solution, by separately providing the pressure relief mechanism from the wall portion and installing it on the wall portion, it is convenient for processing and manufacturing.

[0042] As an alternative technical solution of the embodiment of the present application, the battery cell is a cylindrical battery cell.

[0043] In a second aspect, the embodiment of the present application further provides a battery device, and the battery device includes the above battery cell.

[0044] In a third aspect, an embodiment of the present application further provides an electrical device, which includes the above battery cell, and the battery cell is used to provide electrical energy for the electrical device. Description of the Drawings

[0045] To more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present application, and thus should not be regarded as limiting the scope. For those of ordinary skill in the art, other related drawings can be obtained based on these drawings without creative efforts.

[0046] Figure 1 Structural schematic diagram of a vehicle provided by some embodiments of the present application;

[0047] Figure 2 Explosion view of a battery device provided by some embodiments of the present application;

[0048] Figure 3 Structural schematic diagram of a battery cell provided by some embodiments of the present application;

[0049] Figure 4 Explosion view of a battery cell provided by some embodiments of the present application;

[0050] Figure 5 Structural schematic diagram of a current collector provided by some embodiments of the present application;

[0051] Figure 6 Structural schematic diagram of a first connector provided by some embodiments of the present application;

[0052] Figure 7 Partial cross-sectional view of a battery cell provided by some embodiments of the present application;

[0053] Figure 8 Explosion view of a battery cell provided by some other embodiments of the present application;

[0054] Figure 9 Structural schematic diagram of a current collector provided by some other embodiments of the present application;

[0055] Figure 10 Partial cross-sectional view of a battery cell provided by some other embodiments of the present application.

[0056] Icons: 10 - housing; 11 - first part; 12 - second part; 20 - battery cell; 21 - outer shell; 211 - housing; 2111 - side wall; 2112 - bottom wall; 212 - end cap; 213 - wall portion; 22 - electrode assembly; 221 - main body portion; 222 - tab; 223 - central hole; 23 - pressure relief mechanism; 231 - weak portion; 232 - pressure relief groove; 233 - predetermined pressure relief area; 24 - current collector member; 241 - first connector; 2411 - vent hole; 242 - second connector; 2421 - first connection portion; 2422 - second connection portion; 243 - second area; 2431 - first hollowed - out area; 2432 - second hollowed - out area; 25 - electrode terminal; 100 - battery device; 200 - controller; 300 - motor; 1000 - vehicle. Detailed implementation manners

[0057] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions in the embodiments of this application will be clearly described below with reference to the accompanying drawings in the embodiments of this application. Obviously, the described embodiments are some, but not all, of the embodiments of this application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of this application without creative efforts shall fall within the scope of protection of this application.

[0058] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by those of ordinary skill in the technical field to which this application belongs; the terms used in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the specification and claims of this application and the above - mentioned drawings are intended to cover non - exclusive inclusion. The terms "first", "second", etc. in the specification and claims of this application or the above - mentioned drawings are used to distinguish different objects and are not used to describe a specific order or primary - secondary relationship.

[0059] Referring to "embodiments" in this application means that specific features, structures, or characteristics described in connection with the embodiments can be included in at least one embodiment of this application. The phrase appears in various positions in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments.

[0060] In the description of the present application, it should be noted that unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", and "attached" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected, or indirectly connected through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances.

[0061] The term "and / or" in the present application is merely an association relationship describing associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in the present application generally represents an "or" relationship between the front and rear associated objects.

[0062] In the embodiments of the present application, the same reference numerals represent the same components, and for the sake of brevity, in different embodiments, the detailed description of the same components is omitted. It should be understood that the thickness, length, width, etc. of various components in the embodiments of the present application shown in the drawings, as well as the overall thickness, length, width, etc. of the integrated device are only for illustrative purposes and should not constitute any limitation to the present application.

[0063] The "plurality" mentioned in the present application refers to two or more (including two).

[0064] In the embodiments of the present application, the battery cell can be a secondary battery, and a secondary battery refers to a battery cell that can be activated by charging after the battery cell discharges and can be used continuously.

[0065] The battery cell can be a lithium-ion battery, a sodium-ion battery, a sodium-lithium-ion battery, a lithium metal battery, a sodium metal battery, a lithium-sulfur battery, a magnesium-ion battery, a nickel-metal hydride battery, a nickel-cadmium battery, a lead-acid battery, etc., and the embodiments of the present application are not limited thereto.

[0066] The battery cell generally includes an electrode assembly. The electrode assembly includes a positive electrode, a negative electrode, and a separator. During the charge and discharge process of the battery cell, active ions (such as lithium ions) are embedded and extracted back and forth between the positive electrode and the negative electrode. The separator is disposed between the positive electrode and the negative electrode, which can play a role in preventing short circuit between the positive and negative electrodes to a certain extent, and at the same time allow active ions to pass through.

[0067] In some embodiments, the positive electrode can be a positive electrode plate, and the positive electrode plate can include a positive electrode current collector and a positive electrode active material disposed on at least one surface of the positive electrode current collector.

[0068] As an example, the positive electrode current collector has two surfaces opposite to each other in its own thickness direction, and the positive electrode active material is disposed on any one or both of the two opposite surfaces of the positive electrode current collector.

[0069] As an example, the positive electrode current collector can be a metal foil or a composite current collector. For example, as the metal foil, aluminum with a silver-plated surface, stainless steel with a silver-plated surface, stainless steel, copper, aluminum, nickel, carbon electrode, carbon, nickel, or titanium, etc. can be used. The composite current collector can include a polymer material base layer and a metal layer. The composite current collector can be formed by forming a metal material (such as aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0070] As an example, the positive electrode active material can include at least one of the following materials: lithium-containing phosphate, lithium transition metal oxide, and their respective modified compounds. However, the present application is not limited to these materials, and other conventional materials that can be used as the positive electrode active material of the battery can also be used. These positive electrode active materials can be used alone or in combination of two or more. Among them, examples of the lithium-containing phosphate can include but are not limited to lithium iron phosphate (such as LiFePO4 (which can also be abbreviated as LFP)), a composite material of lithium iron phosphate and carbon, lithium manganese phosphate (such as LiMnPO4), a composite material of lithium manganese phosphate and carbon, lithium manganese iron phosphate, and at least one of a composite material of lithium manganese iron phosphate and carbon. Examples of the lithium transition metal oxide can include but are not limited to lithium cobalt oxide (such as LiCoO2), lithium nickel oxide (such as LiNiO2), lithium manganese oxide (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide (such as LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (which can also be abbreviated as NCM 333 ), LiNi 0.5 Co 0.2 Mn 0.3 O2 (which can also be abbreviated as NCM 523 ), LiNi 0.5 Co 0.25 Mn 0.25 O2 (which can also be abbreviated as NCM 211 ), LiNi 0.6 Co 0.2 Mn 0.2 O2 (which can also be abbreviated as NCM 622 ), LiNi 0.8 Co 0.1 Mn 0.1 O2 (which can also be abbreviated as NCM 811 ), lithium nickel cobalt aluminum oxide (such as LiNi 0.85 Co 0.15 Al 0.05at least one of O2) and its modified compounds, etc.

[0071] In some embodiments, the positive electrode can use a foam metal. The foam metal can be nickel foam, copper foam, aluminum foam, foam alloy, etc. When the foam metal is used as the positive electrode, the positive electrode active material may not be provided on the surface of the foam metal, and of course, the positive electrode active material can also be provided. As an example, a lithium source material, potassium metal or sodium metal can also be filled or / and deposited in the foam metal, and the lithium source material is lithium metal and / or lithium-rich material.

[0072] In some embodiments, the negative electrode can be a negative electrode plate, and the negative electrode plate can include a negative electrode current collector.

[0073] As an example, the negative electrode current collector can use a metal foil, a foam metal or a composite current collector. For example, as the metal foil, aluminum or stainless steel with a silver surface treatment, stainless steel, copper, aluminum, nickel, carbon electrode, nickel or titanium, etc. can be used. The foam metal can be nickel foam, copper foam, aluminum foam, foam alloy, etc. The composite current collector can include a polymer material base layer and a metal layer. The composite current collector can be formed by forming a metal material (such as copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0074] As an example, the negative electrode plate can include a negative electrode current collector and a negative electrode active material provided on at least one surface of the negative electrode current collector.

[0075] As an example, the negative electrode current collector has two surfaces opposite to each other in its own thickness direction, and the negative electrode active material is provided on any one or both of the two opposite surfaces of the negative electrode current collector.

[0076] As an example, the negative electrode active material can use the negative electrode active material for battery monomers well-known in the art. As an example, the negative electrode active material can include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, and lithium titanate, etc. The silicon-based materials can be selected from at least one of elemental silicon, silicon oxides, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. The tin-based materials can be selected from at least one of elemental tin, tin oxides, and tin alloys. However, the present application is not limited to these materials, and other conventional materials that can be used as battery negative electrode active materials can also be used. These negative electrode active materials can be used alone or in combination of two or more.

[0077] In some embodiments, the material of the positive electrode current collector can be aluminum, and the material of the negative electrode current collector can be copper.

[0078] In some embodiments, the electrode assembly further includes a separator disposed between the positive electrode and the negative electrode.

[0079] In some embodiments, the separator is a separator membrane. The types of separator membranes can be various, and any well-known porous structure separator membrane with good chemical stability and mechanical stability can be selected.

[0080] As an example, the material of the separator membrane can include at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, and polyvinylidene fluoride. The separator membrane can be a single-layer film or a multi-layer composite film. When the separator membrane is a multi-layer composite film, the materials of each layer can be the same or different. The separator can be a single component located between the positive and negative electrodes, or can be attached to the surfaces of the positive and negative electrodes.

[0081] In some embodiments, the separator is a solid electrolyte. The solid electrolyte is disposed between the positive electrode and the negative electrode, and simultaneously functions to transport ions and isolate the positive and negative electrodes.

[0082] In some embodiments, the battery cell further includes an electrolyte, which functions to conduct ions between the positive and negative electrodes. The electrolyte can be liquid, gel-like, or solid. Among them, the liquid electrolyte includes an electrolyte salt and a solvent.

[0083] In some embodiments, the electrolyte salt can include at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorooxalate borate, lithium bis(oxalate) borate, lithium difluoro bis(oxalate) phosphate, and lithium tetrafluorooxalate phosphate.

[0084] In some embodiments, the solvent can include at least one of ethylene carbonate, propylene carbonate, ethyl methyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butylene carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, sulfolane, dimethyl sulfone, methyl ethyl sulfone, and diethyl sulfone. The solvent can also be an ether solvent. The ether solvent can include one or more of ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, 1,3-dioxolane, tetrahydrofuran, methyltetrahydrofuran, diphenyl ether, and crown ether.

[0085] Among them, the gel-like electrolyte includes a polymer as the skeleton network of the electrolyte, combined with an ionic liquid-lithium salt.

[0086] Among them, the solid electrolyte includes a polymer solid electrolyte, an inorganic solid electrolyte, and a composite solid electrolyte.

[0087] As an example, the polymer solid electrolyte can be polyether (polyethylene oxide), polysiloxane, polycarbonate, polyacrylonitrile, polyvinylidene fluoride, polymethyl methacrylate, single-ion polymer, polyionic liquid-lithium salt, cellulose, etc.

[0088] As an example, the inorganic solid electrolyte can include oxide solid electrolytes (crystalline perovskite, sodium superionic conductor, garnet, amorphous LiPON film), sulfide solid electrolytes (crystalline lithium superionic conductor (lithium germanium phosphorus sulfur, argyrodite), amorphous sulfide), and one or more of halide solid electrolytes, nitride solid electrolytes, and hydride solid electrolytes.

[0089] As an example, the composite solid electrolyte is formed by adding inorganic solid electrolyte fillers to the polymer solid electrolyte.

[0090] In some embodiments, the electrode assembly is in a wound structure. The positive electrode sheet and the negative electrode sheet are wound into a wound structure.

[0091] In some embodiments, the electrode assembly is in a stacked structure.

[0092] As an example, multiple positive electrode sheets and multiple negative electrode sheets can be respectively provided, and the multiple positive electrode sheets and the multiple negative electrode sheets are alternately stacked.

[0093] As an example, multiple positive electrode sheets can be provided, and the negative electrode sheet is folded to form multiple stacked folding segments, and a positive electrode sheet is clamped between adjacent folding segments.

[0094] As an example, both the positive electrode sheet and the negative electrode sheet are folded to form multiple stacked folding segments.

[0095] As an example, multiple separators can be provided and are respectively arranged between any adjacent positive electrode sheets or negative electrode sheets.

[0096] As an example, the separator can be continuously provided and is arranged between any adjacent positive electrode sheets or negative electrode sheets by folding or winding.

[0097] In some embodiments, the shape of the electrode assembly can be cylindrical, flat, prismatic, etc.

[0098] In some embodiments, the electrode assembly is provided with tabs, and the tabs can conduct current out of the electrode assembly. The tabs include positive tabs and negative tabs.

[0099] In some embodiments, the battery cell can include a housing. The housing is used to encapsulate components such as the electrode assembly and the electrolyte. The housing can be a steel shell, an aluminum shell, a plastic shell (such as polypropylene), a composite metal shell (such as a copper-aluminum composite shell), or an aluminum-plastic film, etc.

[0100] In some embodiments, the outer casing may be a sealed structure or a non-sealed structure. As an example, when the outer casing is a sealed structure, the outer casing can protect the electrode assembly and to a certain extent prevent, for example, electrolyte leakage. When the outer casing is a non-sealed structure, the outer casing can protect the electrode assembly, and a sealed bag may further be included between the outer casing and the electrode assembly, and the sealed bag is used to encapsulate the electrode assembly, the electrolyte, etc. Specifically, the sealed bag may be a bag-shaped insulating member or an aluminum-plastic film.

[0101] As an example, the battery cell may be a cylindrical battery cell, a prismatic battery cell, a pouch battery cell or a battery cell of other shapes. The prismatic battery cell includes, but is not limited to, a square shell battery cell, a blade-shaped battery cell, a multi-prismatic battery, and the multi-prismatic battery is, for example, a hexagonal prism battery, etc.

[0102] The battery device mentioned in the embodiments of the present application refers to a single physical module including one or more battery cells to provide a higher voltage and capacity.

[0103] In some embodiments, the battery device may be a battery module. When there are multiple battery cells, the multiple battery cells are arranged and fixed to form a battery module.

[0104] In some embodiments, the battery device may be a battery pack. The battery pack includes a box body and battery cells, and the battery cells or the battery module are accommodated in the box body.

[0105] In some embodiments, the box body may be a part of the chassis structure of a vehicle. For example, a part of the box body may become at least a part of the floor of the vehicle, or a part of the box body may become at least a part of the cross beam and longitudinal beam of the vehicle.

[0106] In some embodiments, the battery device may be an energy storage device. The energy storage device includes an energy storage container, an energy storage electrical cabinet, etc.

[0107] Currently, from the perspective of the development of the market situation, the application of batteries is becoming more and more extensive. Batteries are not only applied to energy storage power systems such as hydroelectric power plants, thermal power plants, wind power plants and solar power plants, but also widely applied to electric transportation means such as electric bicycles, electric motorcycles, electric vehicles, as well as multiple fields such as military equipment and aerospace. With the continuous expansion of the application fields of batteries, the market demand for them is also continuously increasing.

[0108] The development of battery technology needs to consider multiple design factors simultaneously. For example, performance parameters such as battery life, energy density, discharge capacity, charge and discharge rate, etc. In addition, the reliability of the battery also needs to be considered. However, the current batteries have poor reliability.

[0109] For a battery cell, in order to improve the reliability of the battery cell, in the prior art, a pressure relief mechanism is provided on the end cover. When the internal pressure of the battery cell reaches the detonation pressure, the pressure relief mechanism opens to release the internal pressure of the battery cell, thereby reducing the risk of explosion and fire of the battery cell.

[0110] However, when the current collector member is disposed between the pressure relief mechanism and the electrode assembly, the current collector member will prevent the discharge flow inside the battery cell from flowing towards the pressure relief mechanism, resulting in the battery cell being under pressure, making the battery cell prone to explosion and fire, and resulting in poor reliability of the battery cell.

[0111] In view of this, an embodiment of the present application provides a battery cell. The battery cell includes a housing, an electrode assembly, a pressure relief mechanism, and a current collector member. The housing has a wall portion. The electrode assembly is accommodated in the housing. The pressure relief mechanism is disposed on the wall portion. The current collector member is located between the electrode assembly and the pressure relief mechanism. Wherein, the current collector member includes a first connection body and a second connection body connected to each other. One of the first connection body and the second connection body is connected to the electrode assembly, and the other is connected to the housing. The first connection body is provided with an exhaust hole. Along the thickness direction of the wall portion, the projection of the second connection body is at least partially located in the exhaust hole. The exhaust hole includes a first region covered by the second connection body and a second region not covered by the second connection body. The second region is used to guide the discharge inside the battery cell to the pressure relief mechanism.

[0112] The first connection body of the current collector member is provided with an exhaust hole, and the exhaust hole has a second region not covered by the second connection body, so that the discharge inside the battery cell can flow towards the pressure relief mechanism through the second region, facilitating the rapid pressure relief of the battery cell, reducing the risk of the battery cell being under pressure, and being beneficial to improving the reliability of the battery cell.

[0113] The technical solutions described in the embodiments of the present application are applicable to battery devices and electrical equipment using batteries.

[0114] The electrical equipment can be a vehicle, a mobile phone, a portable device, a laptop computer, a ship, a spacecraft, an electric toy, an electric tool, etc. The spacecraft includes an airplane, a rocket, a space shuttle, a spaceship, etc.; the electric toy includes a fixed or mobile electric toy, for example, a game console, an electric vehicle toy, an electric ship toy, an electric airplane toy, etc.; the electric tool includes a metal cutting electric tool, a grinding electric tool, an assembly electric tool, and a railway electric tool, and may include but is not limited to an electric drill, an electric grinder, an electric wrench, an electric screwdriver, a hammer drill, an impact drill, a concrete vibrator, an electric planer, etc.

[0115] For the convenience of description, the following embodiments take the electrical equipment as a vehicle 1000 as an example for description.

[0116] Please refer to Figure 1 , Figure 1Schematic structural diagram of vehicle 1000 provided by some embodiments of the present application. Vehicle 1000 can be a fuel vehicle, a gas vehicle or a new energy vehicle. The new energy vehicle can be a pure electric vehicle, a hybrid vehicle or an extended-range vehicle, etc. A battery device 100 is disposed inside vehicle 1000. The battery device 100 can be disposed at the bottom, head or tail of vehicle 1000. The battery device 100 can be used for power supply of vehicle 1000. For example, the battery device 100 can be used as the operating power source of vehicle 1000. Vehicle 1000 can also include a controller 200 and a motor 300. The controller 200 is used to control the battery device 100 to supply power to the motor 300. For example, it is used for the working power requirements during the start, navigation and driving of vehicle 1000.

[0117] In some embodiments of the present application, the battery device 100 can not only be used as the operating power source of vehicle 1000, but also as the driving power source of vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for vehicle 1000.

[0118] Please refer to Figure 2 , Figure 2 Explosion diagram of the battery device 100 provided by some embodiments of the present application. The battery device 100 includes a box body 10 and battery cells 20. The battery cells 20 are accommodated in the box body 10. Among them, the box body 10 is used to provide an accommodation space for the battery cells 20, and the box body 10 can adopt various structures. In some embodiments, the box body 10 can include a first part 11 and a second part 12. The first part 11 and the second part 12 are covered with each other, and the first part 11 and the second part 12 jointly define an accommodation space for accommodating the battery cells 20. The second part 12 can be a hollow structure with one end open, and the first part 11 can be a plate-like structure. The first part 11 covers the open side of the second part 12 so that the first part 11 and the second part 12 jointly define an accommodation space; the first part 11 and the second part 12 can also both be hollow structures with one side open, and the open side of the first part 11 covers the open side of the second part 12. Of course, the box body 10 formed by the first part 11 and the second part 12 can be of various shapes, such as a cylinder, a cuboid, etc.

[0119] In the battery device 100, there may be multiple battery cells 20. The multiple battery cells 20 can be connected in series, parallel, or in a hybrid connection. A hybrid connection means that there are both series and parallel connections among the multiple battery cells 20. The multiple battery cells 20 can be directly connected in series, parallel, or in a hybrid connection together, and then the whole formed by the multiple battery cells 20 is accommodated in the box 10. Of course, in the battery device 100, multiple battery cells 20 can also be first connected in series, parallel, or in a hybrid connection to form a battery module, and then multiple battery modules are connected in series, parallel, or in a hybrid connection to form a whole and are accommodated in the box 10. The battery device 100 can also include other structures. For example, the battery device 100 can also include a busbar component for realizing the electrical connection among the multiple battery cells 20.

[0120] Among them, each battery cell 20 can be a secondary battery cell or a primary battery cell; it can also be a lithium-sulfur battery cell, a sodium-ion battery cell, or a magnesium-ion battery cell, but is not limited thereto. The battery cell 20 can be in a cylindrical shape, a flat shape, a cuboid shape, or other shapes, etc.

[0121] Please refer to Figure 3 、 Figure 4 、 Figure 5 、 Figure 6 and Figure 7 , Figure 3 which are schematic structural diagrams of the battery cell 20 provided in some embodiments of the present application. Figure 4 which is an exploded view of the battery cell 20 provided in some embodiments of the present application. Figure 5 which is a schematic structural diagram of the current collector member 24 provided in some embodiments of the present application. Figure 6 which is a schematic structural diagram of the first connector 241 provided in some embodiments of the present application. Figure 7 which is a partial cross-sectional view of the battery cell 20 provided in some embodiments of the present application. Some embodiments of the present application provide a battery cell 20, which includes a housing 21, an electrode assembly 22, a pressure relief mechanism 23, and a current collector member 24. The housing 21 has a wall portion 213. The electrode assembly 22 is accommodated in the housing 21. The pressure relief mechanism 23 is disposed on the wall portion 213. The current collector member 24 is located between the electrode assembly 22 and the pressure relief mechanism 23. Among them, the current collector member 24 includes a first connector 241 and a second connector 242 connected to each other. One of the first connector 241 and the second connector 242 is connected to the electrode assembly 22, and the other is connected to the housing 21. The first connector 241 is provided with an exhaust hole 2411. Along the thickness direction of the wall portion 213, at least a part of the projection of the second connector 242 is located in the exhaust hole 2411. The exhaust hole 2411 includes a first region covered by the second connector 242 and a second region 243 not covered by the second connector 242. The second region 243 is used to guide the emissions in the battery cell 20 to the pressure relief mechanism 23.

[0122] The battery cell 20 refers to the smallest unit that makes up the battery device 100.

[0123] The housing 21 includes an end cap 212 and a housing body 211. The housing body 211 has a receiving space with one end open, and the receiving space is used to receive the electrode assembly 22. The end cap 212 is connected to the housing body 211 and closes the opening.

[0124] The end cap 212 refers to a component that covers the opening of the housing body 211 to isolate the internal environment of the battery cell 20 from the external environment. Without limitation, the shape of the end cap 212 can be adapted to the shape of the housing body 211 to cooperate with the housing body 211. Optionally, the end cap 212 can be made of a material with a certain hardness and strength (such as aluminum alloy). In this way, the end cap 212 is not easily deformed when subjected to extrusion and collision, enabling the battery cell 20 to have higher structural strength and improved reliability. The material of the end cap 212 can include but is not limited to copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc. The battery cell 20 also includes a lower plastic, which is disposed inside the end cap 212 and can be used to isolate the electrical connection components in the housing body 211 from the end cap 212 to reduce the risk of short circuit. Exemplarily, the lower plastic can be plastic, rubber, etc.

[0125] The housing body 211 is a component used to cooperate with the end cap 212 to form the internal environment of the battery cell 20, wherein the formed internal environment can be used to accommodate the electrode assembly 22, the electrolyte, and other components. The housing body 211 and the end cap 212 can be independent components. An opening can be provided on the housing body 211, and the end cap 212 is made to cover the opening at the opening to form the internal environment of the battery cell 20. Without limitation, the end cap 212 and the housing body 211 can also be integrated. Specifically, the end cap 212 and the housing body 211 can first form a common joint surface before other components are inserted into the housing. When it is necessary to encapsulate the interior of the housing body 211, the end cap 212 is then made to cover the housing body 211. The housing body 211 can be of various shapes and sizes, such as rectangular parallelepiped, cylindrical, hexagonal prism, etc. Specifically, the shape of the housing body 211 can be determined according to the specific shape and size of the electrode assembly 22. The material of the housing body 211 can include but is not limited to copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc.

[0126] The electrode assembly 22 is a component in the battery cell 20 where an electrochemical reaction occurs. One or more electrode assemblies 22 can be contained within the housing 211. The electrode assembly 22 is mainly formed by winding or laminating a positive electrode plate and a negative electrode plate, and generally, a separator is provided between the positive electrode plate and the negative electrode plate. The portions of the positive electrode plate and the negative electrode plate having active materials constitute the main body portion 221 of the electrode assembly 22, and the portions of the positive electrode plate and the negative electrode plate without active materials respectively constitute the electrode tabs 222. The positive electrode tab and the negative electrode tab can be located together at one end of the main body portion 221 or separately at both ends of the main body portion 221. During the charge and discharge process of the battery device 100, the positive active material and the negative active material react with the electrolyte.

[0127] The battery cell 20 may further include an electrode terminal 25. The electrode terminal 25 is insulated and installed on the outer shell 21, and the electrode terminal 25 is electrically connected to the electrode assembly 22 to output or input the electrical energy of the battery cell 20. It should be noted that the electrode terminal 25 is insulated and installed on the outer shell 21, that is to say, no electrical connection is formed between the electrode terminal 25 and the outer shell 21. Exemplarily, the material of the electrode terminal 25 can also be various. For example, the material of the electrode terminal 25 can be copper, iron, aluminum, steel, or aluminum alloy, etc.

[0128] The pressure relief mechanism 23 is a component used to open when the internal pressure or temperature of the battery cell 20 reaches the detonation pressure to release the internal pressure of the battery cell 20. The pressure relief mechanism 23 is provided on the wall portion 213. The pressure relief mechanism 23 can be a component installed on the wall portion 213. At this time, the pressure relief mechanism 23 is separately provided and connected to the wall portion 213. For example, the pressure relief mechanism 23 is an explosion-proof film installed on the wall portion 213. The pressure relief mechanism 23 can also be a part of the wall portion 213. At this time, the pressure relief mechanism 23 is integrally formed with the wall portion 213.

[0129] It is possible to determine which wall of the outer shell 21 is the wall portion 213 based on the installation position of the pressure relief mechanism 23. For example, when the pressure relief mechanism 23 is provided on the end cap 212, then the end cap 212 is the wall portion 213. When the pressure relief mechanism 23 is provided on the bottom wall 2112 of the housing 211, then the bottom wall 2112 is the wall portion 213. When the pressure relief mechanism 23 is provided on the side wall 2111 of the housing 211, then the side wall 2111 is the wall portion 213.

[0130] The current collector member 24 is located between the electrode assembly 22 and the pressure relief mechanism 23. The current collector member 24 is used to connect the electrode assembly 22 and the housing 21 to output or input the electrical energy of the battery cell 20 by using the housing 21. Optionally, the current collector member 24 connects the housing 21 and the tabs 222 with the same polarity among the multiple electrode assemblies 22 to achieve the electrical connection between the housing 21 and the multiple electrode assemblies 22, which is beneficial to reducing the assembly difficulty between the tabs 222 and the housing 21. Exemplarily, the material of the current collector member 24 can also be various. For example, the material of the current collector member 24 can be copper, iron, aluminum, steel, aluminum alloy, etc.

[0131] The current collector member 24 includes a first connecting body 241 and a second connecting body 242 connected to each other. One of the first connecting body 241 and the second connecting body 242 is used to connect to the electrode assembly 22, and the other of the first connecting body 241 and the second connecting body 242 is used to connect to the housing 21. For example, when the first connecting body 241 is used to connect to the electrode assembly 22, the second connecting body 242 is used to connect to the housing 21. When the first connecting body 241 is used to connect to the housing 21, the second connecting body 242 is used to connect to the electrode assembly 22.

[0132] Please refer to Figure 4 、 Figure 5 and Figure 7 , the thickness direction of the wall portion 213 is the X direction shown in the figure.

[0133] Among them, the first connecting body 241 is provided with an exhaust hole 2411, and the exhaust hole 2411 is a through hole provided in the first connecting body 241. The exhaust hole 2411 penetrates the first connecting body 241 along the thickness direction of the wall portion 213.

[0134] The second connecting body 242 is connected to the first connecting body 241, and the projection of the second connecting body 242 along the thickness direction of the wall portion 213 is at least partially located in the exhaust hole 2411.

[0135] The exhaust hole 2411 includes a first region and a second region 243. Among them, the first region is the region of the exhaust hole 2411 covered by the second connecting body 242, and the second region 243 is the region of the exhaust hole 2411 not covered by the second connecting body 242. In this way, when the battery cell 20 is depressurized, the emissions in the battery cell 20 can flow through the second region 243 to the pressure relief mechanism 23 and be discharged from the pressure relief mechanism 23 of the battery cell 20 to achieve pressure relief, reducing the risk of explosion and fire of the battery cell 20.

[0136] The first connector 241 of the current collector member 24 is provided with an exhaust hole 2411. The exhaust hole 2411 has a second area 243 that is not covered by the second connector 242, so that the emissions in the battery cell 20 can flow through the second area 243 to the pressure relief mechanism 23, facilitating the rapid pressure relief of the battery cell 20, reducing the risk of pressure buildup in the battery cell 20, and being beneficial to improving the reliability of the battery cell 20.

[0137] Please refer to Figure 3 、 Figure 4 、 Figure 5 、 Figure 6 and Figure 7 , in some embodiments, the second connector 242 includes a plurality of first connection portions 2421. Along the thickness direction of the wall portion 213, the projection of the first connection portion 2421 is located within the exhaust hole 2411. The plurality of first connection portions 2421 are arranged at intervals along the circumferential direction of the exhaust hole 2411 on the first connector 241.

[0138] The exhaust hole 2411 can be a round hole, and the circumferential direction of the exhaust hole 2411 is the circumferential direction of the exhaust hole 2411. Please refer to Figure 5 and Figure 6 , the circumferential direction of the exhaust hole 2411 is the Y direction shown in the figure.

[0139] The second connector 242 can include two first connection portions 2421, three first connection portions 2421, four first connection portions 2421, or more first connection portions 2421. The plurality of first connection portions 2421 are arranged at intervals along the circumferential direction of the exhaust hole 2411 on the first connector 241.

[0140] It should be noted that the projection of the first connection portion 2421 along the thickness direction of the wall portion 213 is located within the exhaust hole 2411.

[0141] The shape of the first connection portion 2421 is not limited. For example, the shape of the first connection portion 2421 can be strip-shaped, fan-shaped, triangular, etc.

[0142] By providing a plurality of first connection portions 2421, on the one hand, the plurality of first connection portions 2421 are all connected to the wall portion 213 or the electrode assembly 22, which is beneficial to increasing the current-carrying area. On the other hand, by arranging the plurality of first connection portions 2421 at intervals along the circumferential direction of the exhaust hole 2411 on the first connector 241, the emissions in the battery cell 20 can flow through the area between two adjacent first connection portions 2421 to the pressure relief mechanism 23, facilitating the rapid pressure relief of the battery cell 20 and being beneficial to improving the reliability of the battery cell 20.

[0143] Please refer to Figure 3 、 Figure 4 、 Figure 5 、 Figure 6 andFigure 7 In some embodiments, the second region 243 includes a first hollow area 2431 and a plurality of second hollow areas 2432. The plurality of first connecting portions 2421 are disposed around the first hollow area 2431, and the first hollow area 2431 is connected to the second hollow area 2432. A second hollow area 2432 is formed between two adjacent first connecting portions 2421.

[0144] The second hollow area 2432 is a region defined by two adjacent first connection portions 2421 and the first connection body 241 in the second region 243. The second region 243 includes a plurality of second hollow areas 2432, which are arranged along the circumference of the exhaust hole 2411.

[0145] The plurality of second hollow areas 2432 are arranged around the first hollow area 2431. The first hollow area 2431 is a region defined by one end of the plurality of first connecting portions 2421 away from the first connecting body 241. Figure 5 The first hollow area 2431 is the area defined by the ends of the six first connecting parts 2421 away from the first connecting body 241. The center of the central hole 223 of the electrode assembly 22 can be used as the center of the circle, and the midpoints of the ends of at least two first connecting parts 2421 away from the first connecting body 241 can be used to fit a virtual circle, and the area defined by the virtual circle is the first area.

[0146] Please refer to Figure 5 , the first hollow area 2431 and the plurality of second hollow areas 2432 are connected.

[0147] By connecting the first hollow area 2431 and the second hollow area 2432, it is beneficial to increase the area of the second area 243, so that the emissions in the battery cell 20 can quickly pass through the collecting component 24 to reach the pressure relief mechanism 23, thereby achieving rapid pressure relief of the battery cell 20, reducing the risk of pressure build-up in the battery cell 20, and helping to improve the reliability of the battery cell 20.

[0148] Please refer to Figure 8 , Figure 9 and Figure 10 , Figure 8 An exploded view of a battery cell 20 provided in accordance with some other embodiments of the present application. Figure 9 Schematic diagram of the structure of the current collecting component 24 provided in some other embodiments of the present application. Figure 10 Partial cross-sectional view of a battery cell 20 provided in some other embodiments of the present application. In some other embodiments, the second connector 242 further includes a second connector portion 2422, and along the thickness direction of the wall portion 213, the projection of the second connector portion 2422 is located in the exhaust hole 2411. The second connector portion 2422 connects multiple first connector portions 2421.

[0149] The second connecting portion 2422 is a component for connecting a plurality of first connecting portions 2421. The projection of the second connecting portion 2422 in the thickness direction of the wall portion 213 is located within the exhaust hole 2411.

[0150] The second connecting portion 2422 may be an annular structure, or the second connecting portion 2422 may be a plate structure. For example, the second connecting portion 2422 is a disc structure.

[0151] By providing the second connecting portion 2422 to connect a plurality of first connecting portions 2421, it is beneficial to increase the structural strength of the second connecting body 242, such that the first connecting portion 2421 is not easily deformed under an external force, and it is beneficial to make the connection between the first connecting portion 2421 and the wall portion 213 or the electrode assembly 22 stable and reliable.

[0152] Please refer to Figure 8 、 Figure 9 and Figure 10 In some embodiments, the second region 243 includes a first hollowed-out area 2431 and a plurality of second hollowed-out areas 2432. A plurality of first connecting portions 2421 are disposed around the second connecting portion 2422. The first hollowed-out area 2431 is located within the second connecting portion 2422. The second connecting portion 2422 separates the first hollowed-out area 2431 and the second hollowed-out areas 2432, and a second hollowed-out area 2432 is formed between two adjacent first connecting portions 2421.

[0153] Please refer to Figure 9 In some embodiments, the second connecting portion 2422 is an annular structure, and the second connecting portion 2422 defines the first hollowed-out area 2431. The second connecting portion 2422, two adjacent first connecting portions 2421, and the first connecting body 241 define a second hollowed-out area 2432. A plurality of second hollowed-out areas 2432 are disposed around the outside of the first hollowed-out area 2431.

[0154] The first hollowed-out area 2431 is located inside the second connecting portion 2422, and the second hollowed-out areas 2432 are located outside the second connecting portion 2422. The second connecting portion 2422 separates the first hollowed-out area 2431 and the second hollowed-out areas 2432, that is, the first hollowed-out area 2431 and the second hollowed-out areas 2432 are not connected to each other.

[0155] The first hollowed-out area 2431 is also provided inside the second connecting portion 2422, which is beneficial to increasing the area of the second region 243, reducing the risk of overpressure in the battery cell 20, and is beneficial to improving the reliability of the battery cell 20.

[0156] In some embodiments, the second connecting portion 2422 is configured to be damaged when the battery cell 20 relieves pressure.

[0157] When the battery cell 20 relieves pressure, the second connecting portion 2422 can be damaged under the action of the internal pressure or emissions of the battery cell 20, so that the area of the second region 243 is larger when the battery cell 20 relieves pressure.

[0158] The second connecting portion 2422 is damaged when the battery cell 20 relieves pressure, so that the area of the second region 243 is larger when the battery cell 20 relieves pressure, which is beneficial to the emissions in the battery cell 20 to quickly pass through the current collector member 24 to reach the pressure relief mechanism 23, realizing rapid pressure relief of the battery cell 20, reducing the risk of pressure buildup in the battery cell 20, and being beneficial to improving the reliability of the battery cell 20.

[0159] Please refer to Figure 8 、 Figure 9 and Figure 10 In some embodiments, the pressure relief mechanism 23 has a weak portion 231, and the pressure relief mechanism 23 is configured to crack along at least a part of the weak portion 231 when the battery cell 20 relieves pressure. The strength of the second connecting portion 2422 is lower than the strength of the weak portion 231.

[0160] The weak portion 231 functions to relieve pressure and is used to enable the pressure relief mechanism 23 to crack along the weak portion 231 when the internal pressure or temperature of the battery cell 20 reaches a predetermined value, so as to relieve the internal pressure of the battery cell 20. For example, the strength of the pressure relief mechanism 23 at the position of the weak portion 231 can be lower than the strength of other positions of the pressure relief mechanism 23. In this way, when the internal pressure or temperature of the battery cell 20 reaches a predetermined value, the first weak portion 231 can crack under the action of the internal pressure to relieve the internal pressure of the battery cell 20.

[0161] The strength of the second connecting portion 2422 is lower than the strength of the weak portion 231, so that the second connecting portion 2422 can be damaged under the action of the internal pressure or emissions of the battery cell 20, and the area of the second region 243 is larger when the battery cell 20 relieves pressure.

[0162] By making the strength of the second connecting portion 2422 lower than the strength of the weak portion 231, when the battery cell 20 relieves pressure, the second connecting portion 2422 is damaged under the action of the emissions of the battery cell 20, further increasing the area of the second region 243, which is beneficial to the emissions in the battery cell 20 to quickly pass through the current collector member 24 to reach the pressure relief mechanism 23, realizing rapid pressure relief of the battery cell 20, reducing the risk of pressure buildup in the battery cell 20, and being beneficial to improving the reliability of the battery cell 20.

[0163] In some embodiments, the second connecting portion 2422 is a ring structure.

[0164] The second connecting portion 2422 can be a circular ring structure, the second connecting portion 2422 can also be an elliptical ring structure, and the second connecting portion 2422 can also be a polygonal structure.

[0165] When the second connecting portion 2422 is in an annular structure, the emissions of the battery cell 20 can flow through the inside of the annular structure to the pressure relief mechanism 23, realizing rapid pressure relief of the battery cell 20, reducing the risk of pressure buildup in the battery cell 20, and being beneficial to improving the reliability of the battery cell 20.

[0166] Please refer to Figure 8 、 Figure 9 and Figure 10 In some embodiments, the electrode assembly 22 has a central hole 223. Along the thickness direction of the wall portion 213, the projection of the hole wall surface of the central hole 223 is located within the first hollowed-out area 2431.

[0167] The electrode assembly 22 includes a positive electrode sheet, a separator, and a negative electrode sheet, and the positive electrode sheet, the separator, and the negative electrode sheet are wound to form a wound structure. During the winding process, the electrode assembly 22 naturally forms a central hole 223.

[0168] The area of the first hollowed-out area 2431 is larger than the area of the central hole 223, and the position of the first hollowed-out area 2431 corresponds to the position of the central hole 223. Along the thickness direction of the wall portion 213, the projection of the contour of the first hollowed-out area 2431 is located outside the hole wall surface of the central hole 223.

[0169] When the projection of the hole wall surface of the central hole 223 is located within the first hollowed-out area 2431, it indicates that the area of the first hollowed-out area 2431 is larger than the area of the central hole 223, thereby facilitating the emissions in the central hole 223 to flow through the first hollowed-out area 2431 to the pressure relief mechanism 23.

[0170] Please refer to Figure 8 、 Figure 9 and Figure 10 In some embodiments, the electrode assembly 22 has a tab 222, and the first connecting portion 2421 is welded to the tab 222.

[0171] The first connecting portion 2421 is welded to the tab 222, and the first connecting body 241 is connected to the wall portion 213, which can make reasonable use of space, make the connection between the current collector member 24 and the electrode assembly 22 and the wall portion 213 more stable, and is also beneficial to making the manufacturing simpler and more convenient, reducing the manufacturing cost of the battery cell 20.

[0172] Please refer to Figure 8 、 Figure 9 and Figure 10 In some embodiments, the first connecting portion 2421 extends along the radial direction of the exhaust hole 2411.

[0173] The radial direction of the exhaust hole 2411 is the extending direction of the diameter of the exhaust hole 2411. Please refer to Figure 10, the radial direction of the exhaust hole 2411 is the Z direction shown in the figure.

[0174] The first connecting portion 2421 extends along the radial direction of the exhaust hole 2411, and the first connecting portion 2421 can be a strip structure.

[0175] By making the first connecting portion 2421 extend along the radial direction of the exhaust hole 2411, it is convenient for the first connecting portion 2421 to be connected to the wall portion 213 or the electrode assembly 22. Especially for a cylindrical battery cell, the first connecting portion 2421 extends in the radial direction of the exhaust hole 2411, and can just be electrically connected to the flattened tab 222.

[0176] Please refer to Figure 8 , Figure 9 and Figure 10 , in some embodiments, the pressure relief mechanism 23 has a weak portion 231, and the pressure relief mechanism 23 is configured to crack along at least a part of the weak portion 231 when the battery cell 20 relieves pressure. The weak portion 231 defines a predetermined pressure relief area 233. Along the thickness direction of the wall portion 213, the projection of the predetermined pressure relief area 233 is located within the exhaust hole 2411.

[0177] The weak portion 231 defines a predetermined pressure relief area 233. When the battery cell 20 relieves pressure, the weak portion 231 cracks along the edge of the predetermined pressure relief area 233, so that the predetermined pressure relief area 233 can be opened to relieve pressure.

[0178] The weak portion 231 can be a closed structure with its head and tail connected, for example, annular. At this time, the predetermined pressure relief area 233 is the area in the pressure relief mechanism 23 circled by the weak portion 231. The weak portion 231 can also be a non-closed structure with a gap between its head and tail, for example, the weak portion 231 can be C-shaped or U-shaped. The line connecting the head and tail of the weak portion 231 is the first connecting line, and the predetermined pressure relief area 233 is the area in the pressure relief mechanism 23 circled by the first connecting line and the weak portion 231.

[0179] The projection of the predetermined pressure relief area 233 along the thickness direction of the wall portion 213 is located within the exhaust hole 2411. In other words, the first connecting body 241 is disposed around the outside of the projection of the predetermined pressure relief area 233 along the thickness direction of the wall portion 213.

[0180] By making the projection of the predetermined pressure relief area 233 located within the exhaust hole 2411, on the one hand, the position of the predetermined pressure relief area 233 corresponds to the position of the exhaust hole 2411, which is convenient for the emissions in the battery cell 20 to reach the pressure relief mechanism 23 through the current collecting member 24. On the other hand, the area of the exhaust hole 2411 is large, which can realize rapid pressure relief of the battery cell 20, reduce the risk of pressure buildup in the battery cell 20, and is beneficial to improving the reliability of the battery cell 20.

[0181] Please refer to Figure 8, Figure 9 and Figure 10 , in some embodiments, the pressure relief mechanism 23 is provided with a pressure relief groove 232, and the pressure relief mechanism 23 forms a weak part 231 in the area where the pressure relief groove 232 is provided. Along the thickness direction of the wall part 213, the projection of the groove bottom surface of the pressure relief groove 232 is located in the exhaust hole 2411.

[0182] The pressure relief mechanism 23 has an inner surface and an outer surface that are oppositely arranged in the thickness direction of the wall part 213. Among them, the inner surface faces the electrode assembly 22, and the outer surface faces away from the electrode assembly 22. It can be that the inner surface is provided with the pressure relief groove 232, or it can be that the outer surface is provided with the pressure relief groove 232. Taking the inner surface being provided with the pressure relief groove 232 as an example, that is, the pressure relief groove 232 is recessed from the inner surface towards the outer surface, and the weak part 231 is the part between the groove bottom surface of the pressure relief groove 232 and the outer surface.

[0183] The pressure relief groove 232 can be processed and formed in various ways, such as stamping forming, cold heading forming, etc. Taking the stamping forming method to form the pressure relief groove 232 as an example, the pressure relief groove 232 can be stamped on the pressure relief mechanism 23 along the thickness direction of the wall part 213.

[0184] Using stamping forming or cold heading to form the pressure relief groove 232 will cause the groove wall of the pressure relief groove 232 to undergo cold work hardening (the grain arrangement changes, resulting in lattice distortion and distortion, reducing the plasticity of the metal and increasing the material hardness), and its ability to resist external impacts is enhanced, and it is not easily damaged by external impact forces. In this way, it is beneficial to reduce the risk of liquid leakage of the pressure relief mechanism 23.

[0185] The projection of the groove bottom surface of the pressure relief groove 232 along the thickness direction of the wall part 213 is located in the exhaust hole 2411.

[0186] When the projection of the groove bottom surface of the pressure relief groove 232 is located in the exhaust hole 2411, the area of the exhaust hole 2411 is larger, and the pressure relief of the battery cell 20 is smoother, which is beneficial to improving the timeliness of the pressure relief of the battery cell 20.

[0187] Please refer to Figure 8 , Figure 9 and Figure 10 , in some embodiments, the pressure relief mechanism 23 has a weak part 231, and the pressure relief mechanism 23 is configured to crack along at least a part of the weak part 231 when the battery cell 20 relieves pressure. The weak part 231 defines a predetermined pressure relief area 233. Along the thickness direction of the wall part 213, the projection of the predetermined pressure relief area 233 is at least partially located in the second area 243.

[0188] By making at least a part of the projection of the predetermined pressure relief area 233 located within the second area 243, that is, at least a part of the predetermined pressure relief area 233 corresponds to the position of the second area 243, it is possible to facilitate the discharge within the battery cell 20 to reach the pressure relief mechanism 23 through the current collector member 24.

[0189] Please refer to Figure 8 、 Figure 9 and Figure 10 , in some embodiments, the pressure relief mechanism 23 has a weak portion 231. The pressure relief mechanism 23 is configured to crack along at least a part of the weak portion 231 when the battery cell 20 relieves pressure, and the weak portion 231 defines a predetermined pressure relief area 233. The area of the second area 243 is larger than the area of the predetermined pressure relief area 233.

[0190] The area of the second area 243 can be characterized by the projected area of the contour of the second area 243 in the thickness direction of the wall portion 213.

[0191] The area of the predetermined pressure relief area 233 can be characterized by the projected area of the predetermined pressure relief area 233 in the thickness direction of the wall portion 213.

[0192] The projected area of the contour of the second area 243 in the thickness direction of the wall portion 213 is larger than the projected area of the predetermined pressure relief area 233 in the thickness direction of the wall portion 213.

[0193] By making the area of the second area 243 larger than the area of the predetermined pressure relief area 233, it is possible to achieve rapid pressure relief of the battery cell 20, reduce the risk of pressure buildup in the battery cell 20, and is beneficial to improving the reliability of the battery cell 20.

[0194] In some embodiments, the first connecting body 241 is directly connected to the wall portion 213, and the second connecting body 242 is connected to the electrode assembly 22.

[0195] The first connecting body 241 can be welded to the wall portion 213, and the second connecting body 242 can be welded to the tab 222 of the electrode assembly 22.

[0196] By connecting the first connecting body 241 to the wall portion 213 and connecting the second connecting body 242 to the electrode assembly 22, it is beneficial to simplify the manufacturing and reduce the manufacturing cost of the battery cell 20.

[0197] In some other embodiments, the housing 21 includes a side wall 2111 that surrounds the wall portion 213 and is connected to the wall portion 213. The first connecting body 241 is directly connected to the side wall 2111, and the second connecting body 242 is connected to the electrode assembly 22.

[0198] The side wall 2111 and the wall portion 213 can be integrally formed. The side wall 2111 and the wall portion 213 then constitute the housing 211. One end of the side wall 2111 away from the wall portion 213 forms an opening of the housing 211. The side wall 2111 and the wall portion 213 can also be separately provided. The wall portion 213 is then an end cap 212. One end of the side wall 2111 close to the wall portion 213 forms an opening of the housing 211.

[0199] When the battery cell 20 is a cylindrical battery cell, the side wall 2111 is cylindrical.

[0200] The first connecting body 241 can be welded to the side wall 2111, and the second connecting body 242 can be welded to the tab 222 of the electrode assembly 22.

[0201] By connecting the first connecting body 241 to the side wall 2111 and connecting the second connecting body 242 to the electrode assembly 22, on the one hand, the electrical energy of the electrode assembly 22 can be output or electrical energy can be input into the electrode assembly 22 through the side wall 2111, facilitating the wiring of the battery cell 20 with other electrically connected components. On the other hand, it is beneficial to simplify the manufacturing and reduce the manufacturing cost of the battery cell 20.

[0202] Please refer to Figure 8 、 Figure 9 and Figure 10 , in some embodiments, the pressure relief mechanism 23 and the wall portion 213 are integrally formed.

[0203] Integrally formed means that the wall portion 213 and the pressure relief mechanism 23 are an integral structure when provided. For example, the pressure relief mechanism 23 can be formed on the wall portion 213 by stamping or cold heading.

[0204] Integrally forming the pressure relief mechanism 23 and the wall portion 213 eliminates the need for additional welding or bonding processes, which is beneficial for reducing the risk of liquid leakage in the pressure relief mechanism 23. Also, during production, it is easy to make the detonation pressures of multiple processed battery cells 20 relatively consistent.

[0205] In other embodiments, the pressure relief mechanism 23 and the wall portion 213 are separately provided. The wall portion 213 is provided with a pressure relief hole, and the pressure relief mechanism 23 is installed on the wall portion 213 and covers the pressure relief hole.

[0206] "The pressure relief mechanism 23 and the wall portion 213 are separately provided. The wall portion 213 is provided with a pressure relief hole, and the pressure relief mechanism 23 is installed on the wall portion 213 and covers the pressure relief hole" means that during manufacturing, a pressure relief hole is opened on the wall portion 213, the pressure relief mechanism 23 and the wall portion 213 are provided separately, and finally connected together. For example, the pressure relief mechanism 23 can be welded to the wall portion 213. The pressure relief mechanism 23 can be an explosion-proof film installed on the wall portion 213.

[0207] By separately providing and installing the pressure relief mechanism 23 on the wall portion 213, it is convenient for processing and manufacturing.

[0208] In some embodiments, the battery cell 20 is a cylindrical battery cell.

[0209] When the battery cell 20 is a cylindrical battery cell, it is more conducive to solving the problem of pressure buildup, and the effect is better.

[0210] The embodiment of the present application also provides a battery device 100, and the battery device 100 includes the above-mentioned battery cell 20.

[0211] The embodiment of the present application also provides an electrical device, and the electrical device includes the above-mentioned battery cell 20, and the battery cell 20 is used to provide electrical energy for the electrical device.

[0212] According to some embodiments of the present application, please refer to Figures 3 to 10 .

[0213] The embodiment of the present application provides a battery cell 20, which includes a housing 21, an electrode assembly 22, a pressure relief mechanism 23, and a current collector member 24. The housing 21 has a wall portion 213. The electrode assembly 22 is accommodated in the housing 21. The pressure relief mechanism 23 is provided on the wall portion 213. The current collector member 24 is located between the electrode assembly 22 and the pressure relief mechanism 23. Among them, the current collector member 24 includes a first connection body 241 and a second connection body 242 connected to each other. One of the first connection body 241 and the second connection body 242 is connected to the electrode assembly 22, and the other is connected to the housing 21. The first connection body 241 is provided with an exhaust hole 2411. Along the thickness direction of the wall portion 213, at least a part of the projection of the second connection body 242 is located in the exhaust hole 2411. The exhaust hole 2411 includes a first area covered by the second connection body 242 and a second area 243 not covered by the second connection body 242. The second area 243 is used to guide the emissions in the battery cell 20 to the pressure relief mechanism 23. The first connection body 241 of the current collector member 24 is provided with an exhaust hole 2411, and the exhaust hole 2411 has a second area 243 not covered by the second connection body 242, so that the emissions in the battery cell 20 can flow to the pressure relief mechanism 23 through the second area 243, which is convenient for the battery cell 20 to quickly relieve pressure, reduces the risk of pressure buildup in the battery cell 20, and is beneficial to improving the reliability of the battery cell 20.

[0214] The second connecting body 242 includes a plurality of first connecting portions 2421. Along the thickness direction of the wall portion 213, the projection of the first connecting portion 2421 is located within the exhaust hole 2411. The plurality of first connecting portions 2421 are arranged at intervals along the circumferential direction of the exhaust hole 2411 on the first connecting body 241. By providing the plurality of first connecting portions 2421, on the one hand, the plurality of first connecting portions 2421 are all connected to the wall portion 213 or the electrode assembly 22, which is beneficial to increasing the current-carrying area. On the other hand, by arranging the plurality of first connecting portions 2421 at intervals along the circumferential direction of the exhaust hole 2411 on the first connecting body 241, the emissions within the battery cell 20 can flow towards the pressure relief mechanism 23 through the area between two adjacent first connecting portions 2421, facilitating rapid pressure relief of the battery cell 20 and being beneficial to improving the reliability of the battery cell 20.

[0215] In some embodiments, the second region 243 includes a first hollowed-out area 2431 and a plurality of second hollowed-out areas 2432. The plurality of first connecting portions 2421 are arranged around the first hollowed-out area 2431, and the first hollowed-out area 2431 communicates with the second hollowed-out areas 2432. One second hollowed-out area 2432 is formed between two adjacent first connecting portions 2421. By making the first hollowed-out area 2431 communicate with the second hollowed-out areas 2432, it is beneficial to increasing the area of the second region 243, so that the emissions within the battery cell 20 can quickly pass through the current collector member 24 to reach the pressure relief mechanism 23, realizing rapid pressure relief of the battery cell 20, reducing the risk of pressure buildup in the battery cell 20, and being beneficial to improving the reliability of the battery cell 20.

[0216] In some other embodiments, the second connecting body 242 further includes a second connecting portion 2422. Along the thickness direction of the wall portion 213, the projection of the second connecting portion 2422 is located within the exhaust hole 2411, and the second connecting portion 2422 connects the plurality of first connecting portions 2421. By providing the second connecting portion 2422 to connect the plurality of first connecting portions 2421, it is beneficial to increasing the structural strength of the second connecting body 242, making the first connecting portion 2421 not easily deform under external force, and being beneficial to making the connection between the first connecting portion 2421 and the wall portion 213 or the electrode assembly 22 stable and reliable.

[0217] The second region 243 includes a first hollowed-out area 2431 and a plurality of second hollowed-out areas 2432. The plurality of first connecting portions 2421 are arranged around the second connecting portion 2422. The first hollowed-out area 2431 is located within the second connecting portion 2422, and the second connecting portion 2422 separates the first hollowed-out area 2431 and the second hollowed-out areas 2432. One second hollowed-out area 2432 is formed between two adjacent first connecting portions 2421. The first hollowed-out area 2431 is also provided within the second connecting portion 2422, which is beneficial to increasing the area of the second region 243, reducing the risk of pressure buildup in the battery cell 20, and being beneficial to improving the reliability of the battery cell 20.

[0218] The second connecting portion 2422 is configured to be destroyed when the battery cell 20 is depressurized. The second connecting portion 2422 is destroyed when the battery cell 20 is depressurized, so that the area of the second region 243 is larger when the battery cell 20 is depressurized, which is beneficial to the rapid passage of the emissions in the battery cell 20 through the current collector member 24 to the pressure relief mechanism 23, realizing the rapid pressure relief of the battery cell 20, reducing the risk of pressure buildup in the battery cell 20, and being beneficial to improving the reliability of the battery cell 20.

[0219] The above are only the preferred embodiments of the present application and are not intended to limit the present application. For those skilled in the art, various changes and modifications can be made to the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A battery cell, characterized in that, Comprising: A housing having a wall portion; An electrode assembly accommodated within the housing; A pressure relief mechanism disposed on the wall portion; A current collecting member located between the electrode assembly and the pressure relief mechanism; Wherein, the current collecting member includes a first connecting body and a second connecting body connected to each other, one of the first connecting body and the second connecting body is connected to the electrode assembly, and the other is connected to the housing. The first connecting body is provided with an exhaust hole. Along the thickness direction of the wall portion, the projection of the second connecting body is at least partially located within the exhaust hole. The exhaust hole includes a first region covered by the second connecting body and a second region not covered by the second connecting body. The second region is used to guide the emissions within the battery cell to the pressure relief mechanism.

2. The battery cell according to claim 1, wherein The second connecting body includes a plurality of first connecting portions. Along the thickness direction of the wall portion, the projection of the first connecting portion is located within the exhaust hole. The plurality of first connecting portions are circumferentially spaced apart along the exhaust hole on the first connecting body.

3. The battery cell according to claim 2, wherein The second region includes a first hollowed-out area and a plurality of second hollowed-out areas. The plurality of first connecting portions surround the first hollowed-out area. The first hollowed-out area is in communication with the second hollowed-out areas. One of the second hollowed-out areas is formed between two adjacent first connecting portions.

4. The battery cell according to claim 2, wherein The second connecting body further includes a second connecting portion. Along the thickness direction of the wall portion, the projection of the second connecting portion is located within the exhaust hole. The second connecting portion connects the plurality of first connecting portions.

5. The battery cell according to claim 4, characterized in that, The second region includes a first hollowed-out area and a plurality of second hollowed-out areas. The plurality of first connecting portions surround the second connecting portion. The first hollowed-out area is located within the second connecting portion. The second connecting portion separates the first hollowed-out area and the second hollowed-out areas. One of the second hollowed-out areas is formed between two adjacent first connecting portions.

6. The battery cell according to claim 4, characterized in that, The second connecting portion is configured to be damaged when the battery cell relieves pressure.

7. The battery cell according to claim 4, wherein The second connecting portion is of an annular structure.

8. The battery cell according to claim 3 or 5, characterized in that, The electrode assembly has a central hole. Along the thickness direction of the wall portion, the projection of the hole wall surface of the central hole is located within the first hollowed-out area.

9. The battery cell according to any one of claims 2-7, characterized in that, The electrode assembly has a tab, and the first connecting portion is welded to the tab.

10. The battery cell according to any one of claims 2-7, characterized in that, The first connecting portion extends radially along the exhaust hole.

11. The battery cell according to any one of claims 1-7, characterized in that, The pressure relief mechanism has a weak portion. The pressure relief mechanism is configured to crack along at least a part of the weak portion when the battery cell relieves pressure. The weak portion defines a predetermined pressure relief area; Along the thickness direction of the wall portion, the projection of the predetermined pressure relief area is located within the exhaust hole.

12. The battery cell according to claim 11, wherein, The pressure relief mechanism is provided with a pressure relief groove. The pressure relief mechanism forms the weak portion in the area where the pressure relief groove is provided; Along the thickness direction of the wall portion, the projection of the bottom surface of the pressure relief groove is located within the exhaust hole.

13. The battery cell according to any one of claims 1-7, characterized in that, The pressure relief mechanism has a weak portion. The pressure relief mechanism is configured to crack along at least a part of the weak portion when the battery cell relieves pressure. The weak portion defines a predetermined pressure relief area; Along the thickness direction of the wall portion, the projection of the predetermined pressure relief area is at least partially located within the second region.

14. The battery cell according to any one of claims 1-7, characterized in that, The pressure relief mechanism has a weak part, and the pressure relief mechanism is configured to crack along at least a part of the weak part when the battery cell relieves pressure, and the weak part defines a predetermined pressure relief area; The area of the second region is larger than the area of the predetermined pressure relief area.

15. The battery cell according to any one of claims 1-7, characterized in that, The first connecting body is directly connected to the wall part, and the second connecting body is connected to the electrode assembly.

16. The battery cell according to any one of claims 1-7, characterized in that, The outer shell includes a side wall, and the side wall surrounds the wall part and is connected to the wall part; The first connecting body is directly connected to the side wall, and the second connecting body is connected to the electrode assembly.

17. The battery cell according to any one of claims 1-7, characterized in that, The pressure relief mechanism is integrally formed with the wall part.

18. The battery cell according to any one of claims 1-7, characterized in that, The pressure relief mechanism is separately provided from the wall part, the wall part is provided with a pressure relief hole, and the pressure relief mechanism is installed on the wall part and covers the pressure relief hole.

19. The battery cell according to any one of claims 1-7, characterized in that, The battery cell is a cylindrical battery cell.

20. A battery device, characterized in that, Comprising the battery cell according to any one of claims 1-19.

21. An electrical device, characterized in that, Comprising the battery cell according to any one of claims 1-19, and the battery cell is used to provide electrical energy for the electrical equipment.

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